1. Field
Embodiments of the present inventive concept relate to a read parameter change scheme, and more particularly, to a method for changing a read parameter for improving a read performance of a non-volatile memory device and apparatuses using the same.
2. Description of the Related Art
Memory devices are divided into volatile memory devices and non-volatile memory devices. In volatile memory devices, data is not retained when power is removed. In non-volatile memory devices, data is retained even when power is removed. Examples of non-volatile memory devices include a read only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), and so on.
A specific type of EEPROM is a flash memory device. A structure and an operation of the flash memory device are different from a structure and an operation of a conventional EEPROM. In particular, the flash memory device may perform an electric erase operation by block and may perform a program operation by bit.
Threshold voltages of a plurality of programmed memory cells included in the flash memory device may change due to various reasons, e.g., floating gate coupling, charge loss as time passes, and so on. A change of threshold voltages of the plurality of memory cells may deteriorate reliability of a read operation in the flash memory device.